Is the Cerebellum a Potential Target for Stimulation in Parkinson's Disease? Results of 1-Hz rTMS on Upper Limb Motor Tasks

Abstract

The aim of this study was to find whether 1-Hz cerebellar repetitive transcranial magnetic stimulation (rTMS) could affect upper limb movement in early-stage Parkinson's disease (PD). Twenty patients with PD underwent one session with real and one with sham rTMS. rTMS (1 Hz, 600 pulses) was targeted at the right lateral cerebellum. Before and after rTMS, patients performed two motor tests with their fingers and hands (ball test, nine-hole peg test). The duration of these tests was measured. There were statistically significant differences (p < 0.05) in the results of the tests after real stimulation and sham stimulation. We excluded the impact of learning. After real rTMS, we observed a significantly faster response in the ball test and a slower response in the nine-hole peg test, both on the right upper limb. This study indicates the influence of 1-Hz cerebellar rTMS in modifying the voluntary movements of the upper limb in PD. This influence is differentiated: the improvement of gross motor skills and the worsening of fine motor skills.

Effect of repetitive transcranial magnetic stimulation over the cerebellum on patients with ataxia after posterior circulation stroke: A pilot study

“…There are several possible explanations for the discrepancy between the hypothesis suggested by the previous studies (16,33) and the results of clinical trials in patients including our studies (8,9). First, because efferent pathways from the cerebellum are connected with both excitatory and inhibitory neurones in the motor cortex, it is difficult to predict whether the modulation of cerebello-cerebral inhibition increases or decreases the excitability of the motor cortex (10,31,34).…”

“…Previous studies of low-frequency cerebellar rTMS in patients with spinocerebellar degeneration have demonstrated improvement in the 10MWT (8,9). In addition, low-frequency rTMS of the cerebellum in Parkinson's disease improved task performance (16), and the decreased cerebellar excitability was associated with better locomotor adaptive learning (15). Based on these results, a low-frequency stimulation protocol was selected in the current study.…”

“…Based on these results, a low-frequency stimulation protocol was selected in the current study. According to some previous studies, which have suggested that decreased Purkinje cell excitability in patients with PCS can decrease cerebello-cerebral inhibition and may lead to ataxia (16,33), the low-frequency cerebellar rTMS could inhibit the excitability of Purkinje cells and further decrease cerebello-cerebral inhibition, which can aggravate the abnormal condition (33). However, we observed that the low-frequency cerebellar rTMS group showed a significant improvement in 10MWT with no harmful effect on balance function measured by BBS, which is consistent with the results of previous studies in patients with spinocerebellar degeneration (8,9).…”

“…It was also reported that 1 Hz rTMS targeted at the lateral cerebellum could induce a faster response in the ipsilateral upper extremity in early-stage Parkinson's disease (16). However, no study has been conducted to determine the effect of cerebellar rTMS on patients with ataxia after PCS.…”

Use of transcranial magnetic stimulation in the treatment of selected movement disorders

“…107 Another study investigated the effects of a single session of 1 Hz rTMS over the right lateral cerebellum on motor performance of the upper limb in early-stage PD, and found that gross motor movements improved and fine motor movements worsened. 108 These studies suggested that the cerebellum plays a role in motor symptoms and motor control in PD and offers a potential locus for rTMS as treatment, particularly with those experiencing LID.…”